In the past year, our core has assisted NHLBI investigators in successfully generating more than one dozen transgenic and knockout mouse lines. Besides these traditional services, the staffs in our core facility are also rigorously learning new skills and developing new capabilities, especially in embryonic stem cell (ESC) and induced pluripotent stem cell (iPSC) research areas. We have successfully derived many lines of mouse and human iPSCs, and become familiar with the methods for characterizing iPSC lines. By using the mouse blastocyst microinjection technique, we have assisted NHLBI scientists in examining the differentiation potential of ESCs and iPSCs into hematopoietic lineages in vivo. We have also devoted a considerable amount of effort in conducting gene-targeting experiments in human iPSCs using the zinc finger nuclease technology. Our goal is to generate several gene-targeted human iPSC reporter lines for facilitating cardiovascular differentiation. We have also been following the cutting edge methodologies for differentiating mouse and human iPSCs into beating cardiomyocytes. In addition, we have devoted a small portion of our effort on finishing up a research project on the characterization of a novel dwarf and obese mouse line generated in our facility using the gene-trapping method.